Galactoseismology: Evidence, Origin, and Implications for Vertical Waves in the Galactic Disk
Larry Widrow
Department of Physics, Queen's University
Tuesday, November 20, 2012

I will present evidence for a North-South asymmetry in the distribution of stars near the Sun based on an analysis of data from the Sloan Digital Sky Survey. The North-South asymmetry has the appearance of vertical waves and may be due to the passage of a satellite galaxy or dark matter subhalo through the disk of the Milky Way. I will also describe recent observations of the outskirts of the Milky Way and Andromeda galaxies where we see enormous stellar streams and arcs. These stellar debris fields may provide important clues as to the formation of galaxies and the distribution of dark matter.